Obstacle crossing behaviour in transfemoral prosthesis users: The effect of prosthetic componentry

Functionally advanced prosthetic ankle-foot and knee components have separately been shown to positively affect obstacle crossing in individuals with a transfemoral amputation. It is unknown, however, what effect combining functionally advanced components has on transfemoral prosthesis users' obstacle-crossing strategies. The study aimed to assess how different knee and ankle-foot prosthetic components influence obstacle-crossing strategies in unilateral transfemoral prosthesis users.

Individuals with a unilateral transfemoral amputation (n = 9) crossed an obstacle (30 cm × 10 cm × 8 cm) placed along an 8.3 m walkway. This was completed in four different prosthetic conditions: a combination of two different knee components (microprocessor and non-microprocessor) with one of two ankle-foot components (rigidly or hydraulically articulating ankles). Full-body kinematics were recorded as participants crossed the obstacles.

Obstacle-crossing strategies were not influenced by the prosthetic component combination. Although small changes were observed in kinematics (joint angles and centre of mass movement) and outcomes such as toe clearance and foot placement, these differences were not statistically significant.

When using different combinations of prosthetic ankle-foot and knee components, lower limb transfemoral prosthesis users make very small changes to movements during obstacle crossing. Obstacle-crossing strategies and outcomes are also not highly influenced by manipulating component use, suggesting relatively high neuromotor flexibility in established unilateral transfemoral prosthesis users when crossing a small obstacle.